The thirty-seventh episode became remarkable for returning the plot to horror-suspense and somber mood, making one of the darkest episodes as far the show has come.

There's some evil in Yuu that makes him quite haunting, as Nene sensed before with her very heart.

I have to point out that the animation went off places, particularly regarding Nene and Yuu's flashback & Lilithmon's fused mode.

Spoiler:

For the projection of the town where the two siblings grew together not only did it possess a depressing and haunting atmosphere, but revive within me the slice-of-real vibes that I got watching way back Digimon Tamers.

Nene and Yuu's flashback came at last not just for delivering drama sake, but also to let in the audience two important devices:

1. Nene and Yuu used to be not only together but very bonded; Nene's shown as a very responsible but kind-hearted older sister, taking care of her little brother.

2. It is alluded in the shadow that influenced Yuu that DarkKnightmon was the culprit behind luring Yuu into the Digital Word via the use of the original, black Xros-Leader. Nene was just a spare that happened to be with Yuu out of DarkKnightmon's original plan, nevertheless, it made use of Nene as we witnessed in the earlier episodes of the show.

Poor Lilithmon. Out of all the Seven Demon Lords who had guest-starred in the previous Digimon series, she got the short-end of the stick.

Spoiler:

Not only getting demoted and ending up acting a subordinate to DarkKnightmon, but her aesthetics got crushed with that ugly Digi-Xros between herself, the Evilmonz, and Blastmon.